Concrete-reenforcing member



LW5 N U cit, 2, 11928..

F. N. SPELLEIR CONCRETE IiEENFORCING MEMBER Filed July 30, 1925 flw/v/r /V. SPELLEE,

lli atented illicit 2i,

T l l B Applicatiqn ,ruee July so, 192.5, fier-ial no. trance:

@llhis invention relates 'to concrete structures and more particularly to a novel form of reenforcing bar for such structures, and has for its object the provision of such a bar having a novel construction, whereby splitting or cracking of the concrete due to the citect of corrosion on the reentorcing bars is entirely eliminated.

lit has been found that the rust formed by corrosion of the reeniorcing bars in many instances splits the concrete due to the pressure exerted by the corroding metal at the surface of the reenforcing members.

The present invention provides for a novel form ot' reeni orcing bar which will collapse at a less pressure than that necessary to break the concrete, and, therefore, prevent the splitting and cracking of the concrete when the corrosion of the reenlorcing bars takes place.

In the drawings- Figure 1 is a sectional elevation through a portion 01": a reenforced concrete wall structure embodying my invention.

Figure 2 is a transverse section through a tube from which my bar is formed.

Figure 3 is a transverse section through a reenlorcing bar constructed in accordance with my invention.

Referring more particularly to the drawings, the numeral 2 designates a concrete wall having my reentorcing rods 3 therein.

The rods 3 may be formed originally in their final shape, or they may first be formed circular as a standard pipe t, shown in Fig- 'ure 2, and then shaped to form the tubular bar 3 having a substantially polygonal crosssection as shown in Figure 3. I

When it is desired to use the hollow reenforcing bars 3 to reentorce concrete, it is only necessary to know the thickness of the covering of concrete and to use the proper gage ot collapsible tubular bar 3 as to eliminate any possibility of the corrosion of the bars splitting the concrete, since if the bars are of the proper gage the pressure exerted by the corrosion will collapse the bar suiliciently to relieve the strain on the concrete.

in order to ascertain the proper gage of hollow reenforcing member to be used it is only necessary to consult any standard reenlforcing table to learn the proper cross section of solid reent'orcing bar necessary to give the desiredstrength, and to then translate the cross-section of the solid bar into the cross-section of a tube having a diameter sutiiciently small to permit a covering of I concrete of a depth sufficient to provide enough strength to collapse the tube rather than fail. That is, the cross-section of metal necessary is known and the thickness of the concrete determines the maximum diameter of the reenforcing member usable, and, therefore, these two elements will determine the gage or Wall thickness of the tubular reeni'orcing member, which gage, 01' course, will vary in direct proportion to the diameter of the tubular reenforcing member used.

in practice, the tubular reeni'orcing members will preferably be made in standard pipe gages and sizes and then deformed to" provide a non-circular collapsible shape.

The reentorcing member 01 Figure 3 is made from the pipe of Figure 2 and has the same cross-sectional. area. The pipe of F ig-v ure 2 has an inside diameter of 1, inches and an outside diameter of 1% inches which gives a cross-sectional area of approximately .69 square inches which is approximately the area of a solid reeni orcing bar having inches diameter, such as a bar also having .69 square inches of cross-sectional area. Therefore, the reeniorcing member of the drawings may be substituted for a solid reentorcing bar of inches diameter and, due to its novel shape, it will collapse under external pressure, less than that necessary to fracture the ordinary two inches or more of concrete covering the reenl'ocing members.

l/Vhile l have shown and described only one form or shape of bar, it will be understood that I do not wish to be limited to the exact shape shown, since various :l'orms of hollow or tubular bars will readily adapt themselves to my invention and may be used without departing from the scope of my invention as defined in the appended claims.

I claim:

1. The combination with a concrete structure of a non-circular hollow collapsible reenforcing member having a cross-section substantially equal to the cross-section required in standard practice for solid reen'forcing bars.

2. The combination wtih a concrete structure of a non-circular hollow reentorcing loo member having a cross-seotion substantially equal to the cross-section required in standard practice for solid reenforcing bars, said hollow reenforcing member having a collapsingpressure over its entire area of less than that required to break the concrete covering said member.- c

3. The combination with a concrete structure of a hollow reenforcing member having a cross-section. substantially equal to the cross-section required in standard practice for solid reenforcing bars said hollow reenforcing' member being collapsible over its entire area by an external pressure less than that necessary to fracture the concrete eovering said member.

4. A hollow reenforcing bar for concrete and the like, having a noncircular, readily collapsible cross-section, the cross-section of said member being substantially equal to the cross-section required in standard practice for solid reenforcing bars.

In testimony whereof, I have hereunto signed my name.

FRANK N. SPELLER. 

